My understanding is different. Maybe you are right but from what I saw she had called Kavin - Anna in one of the previous episodes maybe last week. But Kavin never accepted that he is in a relationship as brother and sister with her. He had many times told her that, and told he is not accepting the term - Anna when she had tried to use it. So from his view he never thought Losliya as sister which she is aware of. So that makes one infer that he is either trying to be just as a friend or maybe as these people tell more than that. When such a guy is pursuing still she cannot say one sided that it’s only brother kind of relationship. Just as you told it seems Losliya is blushing on few occasions which gives a wrong impression. That’s why BB had been focusing on it. Losliya thinks Tharshan as her brother and he too told that she is like a sister. It’s also been shown in a similar way. Anyhow I think we can tell from further episodes about how it all ends. By the way I wanted to tell that I had liked losliya all along until yesterday’s episode. Maybe I will change my opinion again after seeing more BB episodes.